In Switzerland we sometimes have not very well researched articles in the free newspaper '20 Minuten Friday'.They now claim in a video that Google is causing 40% of the CO2 emission of the internet traffic.

Title: Your Google search is bad for the environment.

Translated text:

Does googling pollute the atmosphere?
The internet is immaterial,
but it is stored on physical servers that use electricity.
The biggest part of this energy comes from fossil fuels.
Computing centers emit as much greenhouse gas as the aviation industry.
Google causes 40% of the CO2 results of the internet.
3.5 Mrd google searches per day = 700 tons of CO2.
Google is the biggest user of renewable energy sources.
Nevertheless Google caused 3.2 million tons of CO2 in the past year, he same amount as more than 684000 cars.
Is googleing worth this?

As mentioned I don't really trust this source. Have there been studies on how much CO2 gets produced by "the internet"?

Assuming the translation is correct, the only portion that I can even evaluate is mathematical: If the "searching" specifically causes 700 tons of CO2 per day as claimed, then that's only 250k tons per year. In other words, even if (somehow) everything else in the text is true then searching itself is an extremely small portion of that 3.2 million.
– Kamil DrakariSep 21 '18 at 14:19

1

@KamilDrakari A bit under 10%, not an "extremely" small portion (or a small portion at all) but a far cry from 40%. Also, Google does more than just provide a search engine, so they might include all google activity in this.
– CubicSep 21 '18 at 17:37

In 2015, for instance, it devoured 5.7 terawatt-hours of electricity, about as much as the city of San Francisco uses in a year.

If we assume (justifiably, I think) that Google has both grown and worked to improve its data centres' efficiency, let's call it 6.5 TWh.

The US Energy Information Administration pins CO2 generated per MWh at 1041 lbs, or approximately 475 kg. There are some countries where the generative mix is dirtier, but Google's data centres tend not to be located there.

6.5 million times 475 kg is approximately 3.1 MTonnes.

Now, Google buys and either uses directly or makes available to markets enough renewable, emissions-free energy to completely offset its energy use. But if one assumes that its data centres broadly use a mix of sources similar to those in the US, its carbon dioxide emissions per annum would be close to 3.2 million tonnes.

Of course, globally, emissions are something like 33 Gt per annum, so Google's contribution, notwithstanding their work to bring emissions down, would amount to one one-hundredth of a percent of the total. I would say the benefits accrued by having an index of human knowledge are worth that.

Edit, addendum

Additional point addressing the actual title of the question - a fairly well-sourced study suggests that total data centre energy usage in 2012(!) was circa 269 TWh. Even if the total dropped since then, that puts Google at about 2.5% of total data centre power consumption, not 40%.

It's worth noting that the figure could go up substantially if one counts the energy involved in running the computers, smartphones and other devices connecting to Google, but I don't think the argument could reasonably be made that they wouldn't be used were it not for the search giant.